The chlorofluorocarbon (CFC) propellants currently being used in metered dose inhalers for pulmonary drug delivery are being phased out due to their high ozone depletion potential. An international pharmaceutical industry consortium has proposed that the zero-ozone depletion potential hydrofluoroalkane (HFA) propellants will replace CFCs in metered dose inhalers. There remain, however, crucial reasons to find other drug aerosolization alternatives. Potential problems with the HFA propellants include toxicity, incompatibility with devices, incompatibility with FDA approved inhaler surfactants and reduced bioavailability of some drugs. The investigators have patented a method for the pulmonary aerosol delivery of pharmaceuticals using supercritical fluid carbon dioxide as an inhaler propellant, and have demonstrated its potential usefulness in vivo in several laboratory studies. The investigators have designed a number of inhaler prototypes that use carbon dioxide as a propellant and are seeking funding for additional research and development of these devices. This technology has several advantages including zero-ozone depletion potential propellant, low toxicity of carbon dioxide, and the ability to administer to the lungs lipophilic drugs which cannot currently be delivered by any other method. The investigators propose to improve and thoroughly test a new form of metered dose inhaler which uses carbon dioxide as a propellant. PROPOSED COMMERCIAL APPLICATION: 1. This ozone-friendly technology may replace existing MDI propellants. 2. Aerosol delivery of antibiotics may reduce death from pneumonia. 3. This inhaler may prove to be better than needle injection of insulin. 4. This is an excellent surfactant delivery system to reduce acute lung injury. 5. This may deliver drugs that cannot be administered by any other method.